Transforming growth factor β signalling and matrix metalloproteinases in the mucosa overlying Crohn’s disease strictures
- A Di Sabatino1,
- C L Jackson2,
- K M Pickard2,
- M Buckley2,
- L Rovedatti1,
- N A B Leakey3,
- L Picariello4,
- P Cazzola1,
- G Monteleone5,
- F Tonelli4,
- G R Corazza1,
- T T MacDonald3,
- S L Pender2
- 1First Department of Medicine, Fondazione IRCCS Policlinico S. Matteo, Centro per lo Studio e la Cura delle Malattie Infiammatorie Croniche Intestinali, University of Pavia, Pavia, Italy
- 2Division of Infection, Inflammation and Repair, University of Southampton, School of Medicine, Southampton, UK
- 3Centre for Infectious Disease, Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, London, UK
- 4Department of Clinical Physiopathology, University of Florence, Florence, Italy
- 5Dipartimento di Medicina Interna e Centro di Eccellenza per lo Studio delle Malattie Complesse e Multifattoriali, Università Tor Vergata, Rome, Italy
- Professor T T MacDonald, Centre for Infectious Disease, Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Whitechapel, London E1 2AT, UK; t.t.macdonald{at}qmul.ac.uk
- Revised 8 January 2009
- Accepted 12 January 2009
- Published Online First 6 February 2009
Abstract
Background and Aims: In addition to its crucial role in dampening tissue-damaging immune responses in the gut, transforming growth factor β (TGFβ) is a potent profibrogenic agent inducing collagen synthesis and regulating the balance between matrix-degrading matrix metalloproteinases (MMPs) and their inhibitors (TIMPs). TGFβ signalling was investigated by analysis of Smad proteins and MMPs/TIMPs in the mucosa overlying strictures in patients with Crohn’s disease (CD).
Methods: Specimens were collected from macroscopically normal mucosa overlying strictured and non-strictured gut of patients with fibrostenosing CD. Isolated myofibroblasts were cultured with anti-TGFβ blocking antibody or TGFβ1. TGFβ transcripts were analysed by quantitative reverse transcription-PCR (RT-PCR). Smad proteins and MMPs were determined by immunoblotting. MMP-12 activity was measured by a real-time MMP-12 activity assay. An in vitro wound-healing scratch assay was used to assess myofibroblast migration.
Results: TGFβ transcripts, phosphorylated Smad2–Smad3 (pSmad2–3) and TIMP-1 proteins were higher in mucosa overlying strictures than in mucosa overlying non-strictured areas. In contrast, mucosa overlying strictured gut had lower expression of Smad7, MMP-12 and MMP-3. Myofibroblasts from mucosa overlying strictured gut showed higher TGFβ transcripts, a greater pSmad2–3 response to TGFβ, increased TIMP-1, lower Smad7, increased collagen production and reduced migration ability compared with myofibroblasts from mucosa overlying non-strictured gut. TGFβ blockade increased myofibroblast MMP-12 production and migration, more obviously in myofibroblasts isolated from mucosa overlying non-strictured compared with strictured gut.
Conclusions: Changes in TGF-β signalling and MMP production were identified in the mucosa overlying strictures in CD which may give a window into the process of fibrosis.
Footnotes
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Competing interests: None.
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Ethics approval: Appropriate local Ethics Committee approval was obtained for this study
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Patient consent: Informed consent was obtained in all cases.
